Electric switch.



H. H. BERRY & W. J. MARKHAM.

ELECTRIC SWITCH.

APPLICATION FILED SBPT.16.1918.

1, 1 1 8,324. Patented Nov. 24, 1914.

UNITED STATES PATENT OFFICE.

HERBERT HENRY BERRY AND WILLIAM JAMES MARKI-IAM, OF LONDON, ENGLAND.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Nov. 24=,19114.

Application filed September 16, 1913. Serial No. 790,037.

To all whom it may concern:

Be it known that we, HERBERT HENRY BERRY and WILLIAM JAMES MARKHAM, citi- Zens of the United Kingdom of Great Britain and Ireland, and residents of 78 Upper Thames street, London, England, have invented certain new and useful Improvements in and Relating to Electric Switches, of which the following is a specification, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to electric switches, and particularly switch fuses of the iron clad or armored type.

In armor clad switches and switch fuses it is often the practice to mount the contacts upon porcelain blocks or slate insulators attached to the inside of the base of the case containing the mechanism and while such method of mounting is fairly satisfactory, so far as insulating the said contacts is concerned, the porcelain insulators occupy a considerable amount of room and therefore add to the necessary depth of the case and they are liable to fracture if subjected to excessive heat, mechanical. strain or the shock of gun fire.

The boxes or cases of armored switches are made of cast metal and our invention consists in for-min g integrally with the base or back of the switch, projections or ribs adapted to receive metal contacts of any suitable kind which are insulated by bein wrapped or otherwise sufficiently covered with mica or like flexible material, said contacts being held down by suitable clamping devices.

or the purpose of securely holding the insulators with the metal contacts :in place, we preferably groove the projections and employ short grooved clamps or bridgepieces to fit over the upper sides or edges of the mica insulators.

We willnow describe our invention with reference to the accompanying drawings, in which Figure 1 is a plan view of the bottom of a case. Fig. 2 is a cross sectional view of the same taken substantially on the line A-B of Fig. 1. Fig. 3 is a fragmental sectional view taken substantially on the lines C-D of Fig. 1.

Copies of this patent may be obtained for This case, which is lettered a, is of substantially known form except that it is provided with our grooved projections b adapted to receive the insulated contacts 0 and is also provided with threaded bosses e to receive screws (Z which hold down the bridgelike clamps f.

It must be understood that any suitable form of ribs or projections on the base of the switch may be employed and that the shape of the bridge pieces or equivalents and the method of attaching or adjusting same may be as required but we have found from practice that an ordinary screw as shown in Fig. 2 answers the purpose admil-ably.

It will be seen from Fig. 3 that the contacts c are for the greatest part of their length insulated by mica or like wrappings 0 while the ends are exposed and extend beyond the lugs b giving an unobstructed contact surface.

What we claim and desire to secure by Letters Patent is In an electric switch of the armor clad type, the combination of a cast metal switch box having cast therein integral therewith a plurality of projections having alined outwardly opening grooves, integral threaded bosses also being cast in said box; insulated contact piece suitably wrapped with flexible mica and disposed within said grooves; a perforated insulating bridge-like clamp having a hooked portion adapted to engage over said contact piece in engagement with the insulation thereon; and a screw passed through the perforation of the clamp into said threaded boss and holding the clamp and contact piece in place.

In witness whereof we have hereunto set our hands in presence of two witnesses.

HERBERT HENRY BERRY. WVILLIAM JAMES MARKHAM.

WVitnesses to the signature of Herbert Henry Berry:

ALFRED It. ANDERSON, \VILLIAM I-I. BERRIGAN. lVitnesses to the signature of WVilliam James Markham:

ARTHUR SHnL'roN, CHARLES I'IENRY ALLwooD.

Washington, .D. G. 

